docs: def _get_update_fields(model, uniques, to_update):
      """
      Get the fields to be updated in an upsert.
  
      Always exclude auto_now_add, auto_created fields, and unique fields in an update
      """
      fields = {
          field.attname: field
          for field in model._meta.fields
      }
  
      if to_update is None:
          to_update = [
              field.attname for field in model._meta.fields
          ]
  
      to_update = [
          attname for attname in to_update
          if (attname not in uniques
              and not getattr(fields[attname], 'auto_now_add', False)
              and not fields[attname].auto_created)
      ]
  
      return to_update